Supply line for electric vehicles



March 12, 1940. DQZLER 2,193,623

' SUPPLY LINE FOR ELECTRIC VEHICLES Filed April 22, 1938 Inventor ErnstDozier,

His thorney.

. 2o tions of the supply line.

Patented Mar. 12, 1940 P TENroFFicE $193,623 SUPPLY LINE son ELECTRIC,VEHICLES Ernst Dozler, Berlin steglitz, Germany, assignor to GeneralElectric Company, a corporation of New .York

Application April 22, 1938, Serial'No. 203,695 In Germany April 29,1937' I 1 Claim. (01. 104 -149) My invention'relates to contact powersupply lines for electric vehicles, more particularly to means fordividing the supply line into sections, and has for itsobjccttheprovision' of means 5 providing for regenerative braking whilethe trolley or other contact current-collecting means is passing overthe divider between the sections.

It is well known in connection with contact power supply lines, such asa trolley wire or third rail, to separate the supply line into sectionswhere a plurality of supply sources or substations are provided. Theseseparating points be tween two. adjacent substation sections are formedin a wcll-known'nianner so that nonconducting parts of a predeterminedlength are arranged. over which the current-collecting device on therailway car passes. When'the current is from below by means of a thirdrail, air separating points may be provided between the secelectricvehicle is provided. with several current- I collecting devices whichare connected together on the current supply side, then these divisionsor dividers between the sections of the supply line must be of suchlength as to avoid the connection together of the two adjacent supplyline sections by the plurality of current-collecting devices. When usingelectrical regenerative braking, these points of sub-division are veryunsatisfac tory since an interruption of the braking efiect occurs whenthe current collector on the vehicle passes over the divider portion,and, furthermore, excess voltages in the motors of the vehicle incidentto this interruption of the regenerative brakingcausc protective devicesto be released'which delay a subsequent continuance of regenerativebraking when the collecting devices of the vehicle arrive on the-nextsupply line sec- .40 tlOll.

. In order to avoid these disadvantages in ac cordance with thisinvention, a conductor forming a divider is inserted at the point ofsub-division of the supply line, this conductor being insulated from thetwo adjacent supply line sections and connected to the earth through are-.

sistance. This arrangement prevents interruption of the braking effect,since the motors continue to supply current through this resistance. tis furthermore contemplated, in accordance with the invention, that thisresistance shall have ohmic value selected to give a dynamic-brakingenergy characteristic as near as possible the same as the regenerativebraking characteristic.

55 In that case the passage of the vehicle from one In the event thatthe supply line section to another is effected almost without shock andthe regenerative braking is re- Moreoveizxwith dividers arranged to besep arately' connected to a supply source to make possible the startingof the vehicle while'on the established without difiiculty.

divider where the substation supplies are coupled lar to those of Fig. 2applied to a section divider of considerable length. I

Referring to Fig. 1, the contact power supply line may be either atrolley wire or a third rail. This line iflis separated into twosections it and H at a suitable point between the sources of supply,such as substations, by means of an electrically conducting dividersection II. which is suitably insulated at the points i3 and l l fromthe adjacent ends of thesupply line sections ill, and II.

This divider section i2. is preferably physically similar to theconductors of the sections ill and II and, as. shown, it is arrangedinalignrnent with sections ill and it so as to form mechanicallyacontinuation of these sections over which the trolley orbrakeshoe, asthe case may be,

on the electric vehicle, passes from one section to the other and makeselectrical contact with the divider conductor E2 in passing over it. i

The divider section i2 is furthermore connected electrically to thereturn conductor, such asv the earth l5 oranother trolley wire or thirdrail as the case may be, through an electrical connection it whichincludes a resistance ll. Thus it will be observed that when thecollecting device on the vehicle, such as a trolley 58, engages thedivider section. l2, the motor is on the vehicle' is connectedelectrically directly across the resistance I? so as to supply dynamicbraking current to the resistance ll. This maintains the electricbraking action of the vehicle. Preferably the resistance I l', which maybe a water resistance, has an ohmic value so selected in conformity withthe voltage of the motor it) when acting as a generator duringregenerative braking that the motor I!) will supply a current throughthe resistance I'l approximating the value of its regenerative brakingcurrent supplied to the line section Ill or II in opposition to thevoltage of the supply source. This provides for substantially the sameelectric braking action while the trolley I8 is passing over the dividersection if! whereby variations in the electric braking and consequentshocks are minimized and. the operation of protective devices on thevehicle due to excess voltages is prevented.

The divider section I2 is of such length asto span the collectingdevices in the event that the vehicle is provided with a plurality ofsuch devices electrically connected together but spaced apart along thesupply line. This prevents the electrical connection together throughthe collecting devices of the supply sections [0 and H as would occur ifthe divider section l2 were of insufilcient length to span thecollecting devices. A switch 20 is provided by means of which the twosections l0 and II may be electrically connected together when that isdesirable.

It will be understood that if the section ID or the section II iselectrically connected momentarily to the section l2 by a plurality ofcollecting devices electrically connected together on a vehicle andspanning the insulated points I3 or I l, the momentaiy current from thesupply section through the resistance I! to ground is limited by theresistance I! to a predetermined minimum value approximating the highspeed dynamic braking current through the resistor 11.

In Fig. 2 a double-pole single-throw switch 2| is provided whichnormally, as shown, is in position to connect the divider section 22through a resistance 23 to the ground, the switch being connected to thedivider section 22 through a conductor 24. When the right-hand end ofthe switch member 2| is thrown upward, its left-hand end movingdownward, connections are established through the switch between the twosupply sections 25 and 26 and also through the conductor 24 from thesupply sections to the divider section 22.

In Fig. 3 the divider conductor section 21 is shown of considerablelength to accommodate a plurality of collecting devices on the vehiclespaced apart long distances. In accordance with this arrangement at thepoint of sub-division of the contact supply line, intermediateconducting sections 28 and 29 are provided, these sections beingrelatively short and electrically insulated from the adjoining sectionof the contact supply line and also from the intermediate dividersection 21. By means of a switch 30 the divider section 21 may beelectrically connected together with the short sections 28 and 29through a resistance 3| to earth, as shown. By throwing this switch toits other position the two power supply sections 32 and 33 and theintermediate sections 21, 28 and 29 are all electrically connectedtogether.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto, sincemany modifications may be made and I, there fore, contemplate by theappended claim to cover any such modifications as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

The combination with an electric vehicle power supply line arranged tohave a moving current collecting device contacting therewith to supplycurrent to an electric vehicle arranged for electric regenerativebraking when connected to said supply line, said power supply line beingdivided into two sections having their adjacent ends spaced apart, of anelectrically conducting divider section between said spaced ends inposition to form a mechanical continuation of said supply line sectionsbut electrically insulated from said line sections, a resistance havingan ohmic value such as to provide dynamic braking substantially as greatas said regenerative braking for the motor of a vehicle passing oversaid divider section, means including a two-way switch movable to oneposition to connect electrically said divider section through saidresist ance to a return conductor and movable to another position todisconnect electrically said divider section from said resistance and toconnect electrically said three sections together, said two-way switchand the electrical connections therewith being entirely independent ofthe connection of said supply line sections to sources of electricenergy and being operable to each position without interrupting thesupply of electric energy to said supply line sections.

ERNST DOZLER.

